“It is theoretically possible to travel between two points in the Universe at an effective speed faster than the straight-line speed of light, according to some interpretations of physics.”

In this study, Applied Physics unveils a new type of warp drive—a theoretical method of space travel that complies with general relativity and operates at a constant subluminal speed without requiring unphysical forms of matter. The researchers proved that a class of subluminal warp drives (Class I Warp) can be constructed, in principle, based on the physical assumptions known to humanity today. The researchers hypothesized that there are many more classes of warp drives beyond Alcubierre’s.

However, it does not in itself rule out FTL travel. It is really just one way in which things cannot be made to go faster than light, rather than a proof that there is no way to do so. Even if such 'tachyons' don't exist (and we don't believe that they do exist), there may be ways of moving matter from A to B faster than light is able to travel from A to B by the usual route, but without anything having to go at a FTL speed locally.

In December 2025, a new peer-reviewed study revisited the physics behind warp drives and proposed a refined theoretical design that better fits the equations of general relativity. The research does not claim faster than light travel is achievable today, but it does show that warp geometries can be more flexible than previously thought.

A spacecraft contained in a hyperfast bubble could arrive at its destination faster than light would in normal space without breaking any physical laws. Unlike objects within space–time, space–time itself can bend, expand or warp at any speed. Therefore, a spacecraft contained in a hyperfast bubble could arrive at its destination faster than light would in normal space without breaking any physical laws, even Einstein’s cosmic speed limit.

It is shown how, within the framework of general relativity and without invoking negative energy densities, it is possible to construct spacetime geometries admitting solutions in which a spaceship is able to travel at any desired superluminal speeds. However, enormous energy requirements persist.

In general relativity even this limit can be surpassed, but it will not then be possible to observe both objects at the same time. Again, this is not real faster-than-light travel; it will not help anyone to travel across the galaxy faster than light. All that is happening is that the distance between two objects is increasing faster when taken in some cosmological reference frame.

Scientific understanding of light speed as an absolute natural limit derives from Albert Einstein's publications on special relativity in 1905, confirmed by his work on general relativity in 1916. In classical physics, speed has no limits. But relativistic theory shows that mass increases with acceleration until mass becomes infinite at light speed.

For decades, most physicists considered warp drive to be impossible. But in the past few years, theoretical research has suggested that the fictional technology does not necessarily violate any laws of physics—a discovery that has ignited a wave of interest in creating real warp drive technology. In science fiction, a warp drive is a propulsion system that creates a bubble of spacetime around a spaceship. That bubble is then accelerated to move faster than the speed of light. But spacetime itself can bend or warp at any speed.

The Alcubierre drive conforms to Einstein’s theory of general relativity to achieve superluminal travel. 'By a purely local expansion of spacetime behind the spaceship and an opposite contraction in front of it,' Alcubierre wrote in his paper’s abstract, 'motion faster than the speed of light as seen by observers outside the disturbed region is possible.' The physical model uses almost none of the negative energy.

A warp drive doesn't actually move a spaceship through space faster than light; instead, it manipulates the fabric of spacetime itself. Imagine a region of spacetime being contracted in front of the spacecraft while expanding behind it, creating a "warp bubble." The spaceship would effectively ride this wave, reaching its destination faster than light could travel through ordinary space. In 1994, physicist Miguel Alcubierre proposed a specific solution to Einstein's field equations that described such a warp bubble. The solution is now known as the "Alcubierre metric," and it demonstrates how a localized expansion and contraction of spacetime could theoretically allow for superluminal (faster-than-light) travel.

In 1994, Mexican physicist Miguel Alcubierre published a groundbreaking paper that laid out how a real-life warp drive could work. This exciting development came with a major caveat, however: The proposed "Alcubierre drive" required negative energy, an exotic substance that may or may not exist (or, perhaps, the harnessing of dark energy, the mysterious force that seems to be causing the universe's accelerated expansion). Now, a new paper in the same journal suggests that a warp drive may not require exotic negative energy after all. "By demonstrating a first-of-its-kind model, we've shown that warp drives might not be relegated to science fiction."

However, there is nothing in Einstein’s theory that forbids a particle to move faster than light. You just don’t know how to accelerate anything to such a speed. So really Einstein did not rule out faster than light motion, he just said, no idea how to get there. ... Really as I said, there is nothing in Einstein's theory that forbids it. In fact, this is even easier to see in GR because most space-times (think FRW) have a preferred foliation already.

However, [a modified postulate] permits the existence of objects traveling faster than light. Their existence does not contradict any of the physical consequences of the theory of relativity, since neither the Lorentz transformations nor the relativistic mass law require the velocity of light as an upper limit!

Faster-than-light signaling leads to causality violations and paradoxes in special relativity. No consistent quantum field theory allows tachyons or FTL propagation without breaking Lorentz invariance or unitarity.

In 1994 Miguel Alcubierre was able to construct a valid solution to the equations of general relativity that enable a warp drive. The Alcubierre drive solution appears to violate the strong energy condition because local gravity is repulsive, the dominant energy condition because energy flows faster than the speed of light, and the weak energy condition because it requires negative energy density. These energy conditions are not iron laws of physics but rather reasonable guesses as to how nature makes sense, and while we have no direct proof of their violation, they appear to hold in the natural universe.

Despite an apparent prohibition on such travel by Einstein’s theory of special relativity, the scientists said the theory actually lends itself easily to a description of velocities that exceed the speed of light. 'We started thinking about it, and we think this is a very natural extension of Einstein's equations,' said applied mathematician James Hill... Now, Hill and Cox have extended the theory to accommodate an infinite relative velocity.

In reality, however, Einstein's theory of general relativity shows that it would not be possible for matter to actually cross these “tunnels through space”. In the classical description of general relativity (which neglects quantum effects), it is impossible to cross a wormhole without invoking exotic effects such as time travel.

The reason that we can’t move through space faster than the speed of light is because we are constantly moving through spacetime. We’ve scientifically proven that this is what happens and I direct you to my video on time dilation so you can see one way that we’ve tested that.

This article describes the physics and mathematics behind a class of solutions to the Einstein field equations known as the warp-drive metrics. Parts of this region, however, must also possess negative energy but the requirements are much less than in the original model. So, here we have a warp drive with a very small 'throat' or warp bubble, requiring small negative energies.

Warp drive theory has quickly evolved since the mid-90s, when a concept developed by Mexican physicist Miguel Alcubierre was first described in a landmark paper that provided a scientific basis for hyper-fast travel within general relativity. A new warp-drive study proposes a novel segmented design that could sidestep many of the problems in the original decades-old concept, bringing the possibility of hyper-fast space travel one step closer to becoming a reality.

A new theoretical paper, published in the journal Classical and Quantum Gravity, reignites the debate about the possibility of superluminal (faster-than-light) travel based on conventional physics. However, even recent research about superluminal transport based on Einstein's theory of general relativity would require vast amounts of hypothetical particles and states of matter that have exotic physical properties such as negative energy density.

But I increasingly suspect that going faster than light is not a physical impossibility; instead, in a sense, doing it is “just” an engineering problem. Do we allow an existing “space tunnel” (like the wormholes of general relativity)? Perhaps a space tunnel that has been there since the beginning of the universe. Or even if no space tunnel already exists, do we allow the possibility of building one—that we can then travel through?

New research proposes several methods through which FTL travel might be possible. Most propositions for FTL travel propose a way to manipulate this spacetime fabric itself, creating a kind of warp or shortcut that would allow a spacecraft to travel faster than the speed of light. FTL wouldn’t be about the spacecraft pushing itself to faster speeds than light, which is considered impossible, but rather about warping spacetime around it to create a faster path or a shortcut.

The theoretical physicist Miguel Alcubierre published a remarkable paper which grew from his work in general relativity, describing a very unusual solution to Einstein's equations of general relativity, described in the title as a "warp drive", and in the abstract as "a modification of space time in a way that allows a space ship to travel at an arbitrarily large speed". The Alcubierre drive is similar to stable wormholes: they are solutions to the equations of general relativity, but one would need "exotic matter" with negative mass-energy to actually produce them, and we have none at the moment. The possibilities for FTL travel or communication implicit in the Alcubierre drive raise the possibility of causality violations and "timelike loops", i.e., back-in-time communication and time travel.

The warp drive concept, based on the Alcubierre metric, offers a theoretical method for spaceships to travel faster than the speed of light. Warp drive's ability to seemingly break the universal speed limit lies in its exploitation of space-time. According to general relativity, space and time are interconnected, and space-time itself does not contain any information.

Miguel Alcubierre's 1994 paper 'The warp drive: hyper-fast travel within general relativity' proposes a solution to Einstein's field equations allowing a spaceship to travel at effective superluminal speeds by contracting spacetime in front and expanding it behind, without locally exceeding the speed of light. This is a theoretical interpretation in general relativity, though it originally required negative energy density, which remains unphysical.

His theory is entirely compatible with faster than light travel... The argument that faster than light travel is impossible is that we know our current theory of SpaceTime general relativity can't be correct because it doesn't work together with quantum theory... This is why I think it's extremely implausible that any argument about faster than light travel would survive in the to be found theory of quantum gravity.